1. Field of the Invention
The present invention relates to security devices; and more particularly to latches for securing the edges of pivotally mounted doors, gates, and similar closure units.
The rising crime rate and the increased perception of insecurity, even within one's own home, has given impetus to the use of "extra protection" security devices. Unlike conventional locks, these devices are enabled or activated when the occupant is within their dwelling. They are controlled from the inside and do not require keys.
The principle characteristic of such devices is their effectiveness. Generally these devices should not be accessible to anyone except from within the premises. They should be at least as strong as the door and frame structures to which they are attached. They must not be subject to dislodgement during attempts to breach the security of the premises.
Optimally, these devices are manually operable, easy to understand without instructions, permanently affixed to the structures being protected, conspicuous--yet not obtrusive. Aged and handicapped people, and the strictures of the current Americans with Disabilities Act, require recognition that there may be limited visual acuity and dexterity available. Blind people and those without the availability of digital dexterity should be able to use these security devices
2. Description of the Prior Art
Locks and latches are among the most ancient interests of property owners and they have long stimulated the minds and creativity of inventors and security specialists. Where two juxtaposed objects are to be fastened, it is conventional to mount a stationary apertured plate on one member and a movable element on the other member for selective interlocking engagement. In lieu of better devices, slide-bolts, braces, and bars are frequently used.
The 1874 Patent to Blackman, U.S. Pat. No. 148,919, illustrates a latch for mounting on the adjacent edges of double hung sash, including a lever on one sash having locking arms adapted to engage a keeper on the other. The 1890 Patent to Woodard, U.S. Pat. No. 420,290, reveals an adaptation of this basic principle to coffin fasteners. Conventional slide bolts with a translatable bolt on the door, adapted to engage a fixed plate on the adjacent door jamb, need no illustration to elicit recognition and understanding.
The Kerler latch in U.S. Pat. No. 538,078, is not designed for security, but illustrates the pivotal mounting of a movable latch member to effect engagement and disengagement to a fixed plate as a door is closed and opened. Unlike the preferred characteristics of the present invention, to accommodate the keeper, this device requires undesirable cut-outs in the door and frame.